The present study deals with the hydrology of two adjoining watersheds, located in an area where average annual rainfall is ~280 mm. One watershed is located in a loess covered area, and the second in a rocky area. Hydrological data collected in the loess area point to a very high frequency of channel flow. However, even in extreme rain events, peak discharges are extremely low, pointing to a limited contributing area. The explanation proposed is that runoff generation is limited to the channel area, where a quasi-permanent seal, very rich in dispersive clays, responds quickly to low rain intensities. The contribution of the adjoining hillslopes is negligible. The hydrological regime in the rocky area is opposite. The frequency of overland flow is very high. However, channel flow did not develop, even in an extreme rain event of 105 mm with peak rain intensities of 90 mm/h¹ in 2 min. The hydrological dis-connectivity at the-hillslope-channel interface is explained by the local rainfall characteristics. Rainstorms are highly intermittent, and the concentration time required for a continuous flow, along a whole slope, is much longer than the duration of most effective intermittent rain showers. Data obtained limit the possibility of extrapolation hydrological data from one area to another, under the same rainfall regime.

本研究涉及两个相邻流域的水文学，这两个流域位于年平均降水量约为280毫米的地区。一个分水岭位于黄土覆盖地区，第二个分水岭位于岩石地区。在黄土地区收集的水文数据表明河道流量非常高。但是，即使在极端降雨的情况下，峰值流量也极低，这表明作用区域有限。提出的解释是，径流的产生仅限于河道区域，在该区域中，准永久性海豹非常富含分散性粘土，对雨水强度低做出快速反应。毗邻的山坡的贡献可以忽略不计。岩石区的水文状况则相反。陆流的频率非常高。但是，渠道流并未发展，2分钟¹分。坡道通道界面的水文非连通性由局部降雨特征解释。暴雨是高度断断续续的，并且沿着整个斜坡连续流动所需的集中时间比最有效的间歇性淋浴的持续时间长得多。在相同的降雨制度下，获得的数据限制了从一个地区向另一地区外推水文数据的可能性。